package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCDemo8 {
    public static void main(String[] args) {
        try(Connection conn = DBUtil.getConnection()) {
            Statement statement = conn.createStatement();
            String sql = "SELECT COUNT(*) count,c.name " +
                    "FROM class c " +
                    "JOIN student s ON c.id = s.class_id " +
                    "GROUP BY c.name";
            ResultSet rs = statement.executeQuery(sql);
            while(rs.next()){
                int count = rs.getInt("count");
                String name = rs.getString("c.name");
                System.out.println("人数："+count+"班级："+name);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}
